This invention relates to a method of preparing a magnetostrictive material using a micro-gravity environment.
Magnetostriction is the property of a body of material to change the shape thereof when the state of magnetization thereof is changed. Magnetostriction of a transition metal material containing a rare earth element is about 100 times as great as the corresponding material containing no rare earth element. Such a magnetostrictive material having a high magnetostriction is generally called super-magnetostrictive material and may be utilized for many applications, for example, actuators, pressure sensors, ultrasonic generation devices.
The Czochralski (Cz) method and the floating zone (Fz) method have been proposed for the fabrication of a magnetostrictive material. Since these methods are ill-suited for the production of a high performance magnetostrictive material, however, the recent trend is toward the use of film forming techniques such as sputtering and vacuum deposition.
In accordance with the present invention there is provided a method of preparing a magnetostrictive material, comprising the steps of:
(a) forming a melt of metals having a composition corresponding to the magnetostrictive material;
(b) subjecting said melt to a micro-gravity environment; and
(c) cooling said melt in the micro-gravity environment at a rate of at least 50xc2x0 C. per second, while applying a magnetic field to said melt, to solidify said melt.
It is an object of the present invention to provide a method of preparing a magnetostrictive material within a short period of time and at low costs.
Another method of the present invention is to provide a method which can produce high performance super-magnetostrictive material.